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FORMATION OF THE RINGS OF WOOD IN TREES. 



HE many differences of opinion that even eminent, men are pre- 

 sumed to hold in regard to the character of the so-called annual 

 rings of trees, would be readily reconciled if a little thought 

 were given to the manner in which wood is formed as the trunk is 

 enlarged. This is accomplished by the birth of new cells, which 

 proceed laterally from the old ones. The new course of cells take 

 their place around the mother cells, and form a thin layer over 

 them, just as if a sheet of writing paper might be wrapped around another. 

 These in a few days again become mother cells, and another course is produced. 

 This continues during the short time devoted to growth, perhaps a dozen times, 

 and the mass of new wood known as the new annual layer, is really made up of 

 a dozen fine layers so small that the concentric lines are only visible by means 

 of a powerful microscope. Now the size of these cells depends on the amount 

 of material at command. The original mother cell that starts the annual growth, 

 has had the advantage of the best opportunities for stored nutrition, every suc- 

 cessive addition is weaker and weaker, until the last growths of the season are 

 very small. It is because they are so small and packed close together that we 

 can readily see where they end, and thus detect the extent of the annual layer 

 even in old trees. Now a tree may be in a position to have command over a 

 superior stock of nutrition, and the cells are in a condition to avail themselves 

 of the advantages, especially if the cells are naturally of a large size, as they are 

 in some trees. In the Europeah silver linden, for instance, the cells are one- 

 fourth larger than they are in the common American linden ; and in this and 

 similar trees, a number of light rings can usually be traced in the annual incre- 

 ment. The same can often be seen in vigorous specimens of the cottonwood. 

 But plainly as these lines may be seen, the experienced investigator can rarely 

 be mistaken on the last line made during the growing season, and is able to tell 

 how many years the tree has been growing on the spot where it stands. There 

 is nothing more certain than that in the hand of an expert the age of a tree can 

 be determined by its annual growths. —Gardener's Monthly. 



ZINNIA HAAGENA. 



I was only introduced to Zinnia Haagena this year, but am sorry I didn't 

 make its acquaintance sooner, as it is a naost desirable variety, all yellow, and 

 much better for boquet use than the ordinary kinds. In the present craze for 

 yellow flowers, everybody ought to have it. Anthemes Coronana fl. pi. is 

 another yellow flower I think a great deal of. It is a very free-growing plant, 

 abundant bloomer, and lemon yellow. Zinnia Haagena is orange. 



Cornwall^ Ont. C. VV. Young. 



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